The goal of the proposed experiments is to provide a thorough description of an important class of retinal neurons, the peptidergic cells in an animal model which closely resembles the human. This series of studies will be the beginning of a complete description of the interconnections of specific types of neurons in the primate innerplexiform layer. In light microscopic immunolabeling, I will describe the morphology frequency and regional distribution of these cells. The cells in the central retina will be labeled by the immunoperoxidase technique and reconstructed from serial electron micrograph to study their synaptic connections and deduce their roles in visual information processing. I will look for all the peptides reported to date in vertebrate eyes, beginning with the five already known to exist in primate retina. All other ocular tissue will be labeled by the same technique and reserved for future analysis. The modified fixation and immunolabeling technique developed for the project would also be applicable to material from human donors.